Retaining walls on hillside properties
By Dan Jones ·
Bottom line: in Penticton a retaining wall over 1.2 metres, about four feet, requires an engineered design as part of its permit, and so does a wall carrying a load such as a driveway or a structure above it. On a hillside lot the walls can be the most expensive thing outside the house itself, and the question worth asking is whether a substantial wall was designed or whether somebody stacked it. When walls fail they almost always fail from water rather than weakness. Drainage behind the wall that was never installed properly, or that has silted up over twenty years, leaves the wall holding back saturated soil it was never meant to carry. That is why a wall stands for decades and then moves in one wet spring, and why a leaning wall is a number to establish before you set a price, not a cosmetic job to tidy before photos.
I am Dan Jones, a REALTOR with Royal LePage Locations West in Penticton, licence number 1118346. I built houses for twenty-four years as a Red Seal journeyman carpenter before I was licensed in 2004, and on a lot of those sites the retaining wall and its drainage went in before anything else did.
I am not an engineer. I can tell you what I see from the ground and what it tends to mean for a sale. What a wall needs, and what it will cost, is an engineer’s call.
Why this valley has so many
A lot of Penticton is built on slopes. The benches, the hillsides above Skaha, the east side up toward the Naramata road, the newer developments stepping up the hills. A sloped lot means ground being held back somewhere, and that is a retaining wall even when nobody thinks of it as one.
Some of those walls are engineered concrete with proper footings and drainage. Some are stacked block that looks the same from the street. Some are timber from the 1970s that has quietly been rotting at the base for a decade.
From a listing photo, they can all look fine.
What the City requires
Two separate rules, from two different parts of City Hall.
The building side. An engineered design is required as part of a retaining wall permit where the wall exceeds 1.2 metres in height, or where there is superimposed loading, meaning something bearing on the soil behind it, such as a driveway, a garage, a pool, or another wall stepped above.
That second trigger catches people. A three foot wall with a parking pad right behind it can need engineering that a free-standing four foot garden wall would not.
The zoning side. The zoning bylaw generally limits retaining walls within required yard setbacks to 1.2 metres. A taller wall in a setback needs a Development Variance Permit on top of the building permit. That is a planning approval with its own process and timeline, not a building department formality.
The City also publishes a building bulletin on geotechnical requirements, which sets out when a geotechnical engineer has to be involved. For anyone buying a slope lot to build on, that bulletin is worth reading before you commit to a design.
Requirements are property specific and they change. Check with the City for the address in question, including what applied when an existing wall went in, which may differ from today.
Why walls actually fail
Here is the part that is worth understanding, because it changes what you look for.
A retaining wall is designed to hold back soil. Soil is heavy, but it is a predictable load.
Water is the problem. Saturated soil is far heavier than dry soil, and water trapped behind a wall adds pressure that the wall was not designed to resist. A properly built wall has drainage behind it, typically free-draining gravel and a perforated drain pipe at the base, precisely so water can get out rather than build up.
When that drainage was never installed, or was installed and has silted up over twenty years, or the outlet has been buried by landscaping, the wall is quietly carrying a load it was never meant for.
It then does nothing visible for a very long time. And then one wet spring, or one heavy snowmelt, or one irrigation line leaking behind it for a season, it moves.
So a wall that has stood for twenty five years is not proof it is sound. It may simply be proof it has not had its bad year yet.
What I look for from the ground
- Leaning or tilting away from the slope, even slightly, which is easiest to see by sighting along the top of a run
- Bulging in the middle of a run
- Stepped cracking through block or mortar joints
- Blocks or timbers separating at the joints
- Soil or gravel washing out through gaps or over the top
- Wet ground, staining or efflorescence at the base, which says water is coming through rather than being drained away
- Timber walls soft or crumbling at ground level
- No visible drain outlets anywhere along a substantial wall
None of that tells you whether the wall is permitted or engineered. It tells you whether the wall is behaving.
Property lines
Walls near a boundary raise a separate question: whose is it?
That depends on where the wall physically sits, which a survey establishes, and on what is registered on title, which may include an easement or covenant. A wall holding up your neighbour’s yard, sitting on your side of the line, is an uncomfortable thing to discover after completion.
Responsibility for a shared or boundary wall is a legal question. If one is involved, ask a lawyer before you remove subjects.
If you are selling
Do not tidy a leaning wall before listing. A buyer’s inspector will flag it regardless, and a freshly patched wall invites more suspicion than an honest one.
What I would do:
- Ask the City for the permit history. If there is an engineered design and a permit on file, that paperwork is worth real money at sale.
- If the wall is showing any of the signs above, get an engineer’s opinion before you set the price.
- Get a real number for what it needs.
- Decide whether to repair or to price it in, with that number in hand.
The worst version is a buyer’s inspection finding it on day six, a buyer’s contractor guessing at a cost on day eight, and you negotiating against a guess that is almost always higher than reality.
If you are buying
On a hillside property, walk every wall, not just the ones near the house.
Ask for the permit history. Ask whether any engineering is on file. If a substantial wall shows movement, make an engineer’s assessment a condition, and do it before subject removal rather than after.
If you intend to build or add to the property, read the City’s geotechnical bulletin before you fall in love with a plan, because a slope lot can carry costs that a flat lot never does.
Where this sits
On hillside properties, retaining walls and the driveway often tell the same story, because both are responding to what water and soil are doing. Cracks in a driveway can be a symptom of the same movement. The full older-house list is here, and if the property is in a hillside development with private roads and shared walls, bare land strata ownership changes who pays for what.
Requirements above come from the City of Penticton and are current as of September 2026. They are property specific and they change. Confirm with the City before relying on them.
If you are looking at a hillside property and want someone to walk the walls with you, email me at dano007@shaw.ca or call 250.488.0226.